Change Puma.stats to return a hash instead of a JSON string

Having access to the hash allows to produce stats in other ways (such as StatsD) without having to parse JSON of data that is available in memory. An example of this workaround is https://github.com/yob/puma-plugin-statsd/blob/fa6ba1f5074473618643ef7cf99747801a001dec/lib/puma/plugin/statsd.rb#L112-L114

History.md

@@ -3,6 +3,7 @@
 * Features
   * Add pumactl `thread-backtraces` command to print thread backtraces (#2053)
   * Configuration: `environment` is read from `RAILS_ENV`, if `RACK_ENV` can't be found (#2022)
+  * `Puma.stats` now returns a Hash instead of a JSON string (#2086)
 
 * Bugfixes
   * Your bugfix goes here (#Github Number)

lib/puma/app/status.rb

@@ -54,7 +54,7 @@ def call(env)
           rack_response(200, GC.stat.to_json)
 
         when /\/stats$/
-          rack_response(200, @cli.stats)
+          rack_response(200, @cli.stats.to_json)
 
         when /\/thread-backtraces$/
           backtraces = []

lib/puma/cluster.rb

@@ -73,7 +73,7 @@ def initialize(idx, pid, phase, options)
         @first_term_sent = nil
         @started_at = Time.now
         @last_checkin = Time.now
-        @last_status = '{}'
+        @last_status = {}
         @term = false
       end
 
@@ -94,7 +94,11 @@ def term?
 
       def ping!(status)
         @last_checkin = Time.now
-        @last_status = status
+        captures = status.match(/{ "backlog":(?<backlog>\d*), "running":(?<running>\d*), "pool_capacity":(?<pool_capacity>\d*), "max_threads": (?<max_threads>\d*) }/)
+        @last_status = captures.names.inject({}) do |hash, key|
+          hash[key.to_sym] = captures[key].to_i
+          hash
+        end
       end
 
       def ping_timeout?(which)
@@ -352,9 +356,26 @@ def reload_worker_directory
     # the master process.
     def stats
       old_worker_count = @workers.count { |w| w.phase != @phase }
-      booted_worker_count = @workers.count { |w| w.booted? }
-      worker_status = '[' + @workers.map { |w| %Q!{ "started_at": "#{w.started_at.utc.iso8601}", "pid": #{w.pid}, "index": #{w.index}, "phase": #{w.phase}, "booted": #{w.booted?}, "last_checkin": "#{w.last_checkin.utc.iso8601}", "last_status": #{w.last_status} }!}.join(",") + ']'
-      %Q!{ "started_at": "#{@started_at.utc.iso8601}", "workers": #{@workers.size}, "phase": #{@phase}, "booted_workers": #{booted_worker_count}, "old_workers": #{old_worker_count}, "worker_status": #{worker_status} }!
+      worker_status = @workers.map do |w|
+        {
+          started_at: w.started_at.utc.iso8601,
+          pid: w.pid,
+          index: w.index,
+          phase: w.phase,
+          booted: w.booted?,
+          last_checkin: w.last_checkin.utc.iso8601,
+          last_status: w.last_status,
+        }
+      end
+
+      {
+        started_at: @started_at.utc.iso8601,
+        workers: @workers.size,
+        phase: @phase,
+        booted_workers: worker_status.count { |w| w[:booted] },
+        old_workers: old_worker_count,
+        worker_status: worker_status,
+      }
     end
 
     def preload?

lib/puma/single.rb

@@ -14,11 +14,13 @@ module Puma
   # that this inherits from.
   class Single < Runner
     def stats
-      b = @server.backlog || 0
-      r = @server.running || 0
-      t = @server.pool_capacity || 0
-      m = @server.max_threads || 0
-      %Q!{ "started_at": "#{@started_at.utc.iso8601}", "backlog": #{b}, "running": #{r}, "pool_capacity": #{t}, "max_threads": #{m} }!
+      {
+        started_at: @started_at.utc.iso8601,
+        backlog: @server.backlog || 0,
+        running: @server.running || 0,
+        pool_capacity: @server.pool_capacity || 0,
+        max_threads: @server.max_threads || 0,
+      }
     end
 
     def restart

test/test_app_status.rb

@@ -24,7 +24,7 @@ def halt
     end
 
     def stats
-      "{}"
+      {}
     end
   end
 

test/test_cli.rb

@@ -57,8 +57,7 @@ def test_control_for_tcp
     body = s.read
     s.close
 
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, body.split(/\r?\n/).last)
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, Puma.stats)
+    assert_match(/{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/, body.split(/\r?\n/).last)
 
   ensure
     cli.launcher.stop
@@ -92,9 +91,9 @@ def test_control_for_ssl
       body = http.request(req).body
     end
 
-    expected_stats = /{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/
+    expected_stats = /{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/
     assert_match(expected_stats, body.split(/\r?\n/).last)
-    assert_match(expected_stats, Puma.stats)
+    assert_equal([:started_at, :backlog, :running, :pool_capacity, :max_threads], Puma.stats.keys)
 
   ensure
     cli.launcher.stop
@@ -137,7 +136,7 @@ def test_control_clustered
     body = s.read
     s.close
 
-    assert_match(/\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "workers": 2, "phase": 0, "booted_workers": 2, "old_workers": 0, "worker_status": \[\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "pid": \d+, "index": 0, "phase": 0, "booted": true, "last_checkin": "[^"]+", "last_status": \{ "backlog":0, "running":2, "pool_capacity":2, "max_threads": 2 \} \},\{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "pid": \d+, "index": 1, "phase": 0, "booted": true, "last_checkin": "[^"]+", "last_status": \{ "backlog":0, "running":2, "pool_capacity":2, "max_threads": 2 \} \}\] \}/, body.split("\r\n").last)
+    assert_match(/\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","workers":2,"phase":0,"booted_workers":2,"old_workers":0,"worker_status":\[\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","pid":\d+,"index":0,"phase":0,"booted":true,"last_checkin":"[^"]+","last_status":\{"backlog":0,"running":2,"pool_capacity":2,"max_threads":2\}\},\{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","pid":\d+,"index":1,"phase":0,"booted":true,"last_checkin":"[^"]+","last_status":\{"backlog":0,"running":2,"pool_capacity":2,"max_threads":2\}\}\]\}/, body.split("\r\n").last)
   ensure
     if UNIX_SKT_EXIST && HAS_FORK
       cli.launcher.stop
@@ -172,7 +171,7 @@ def test_control
     body = s.read
     s.close
 
-    assert_match(/{ "started_at": "\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z", "backlog": 0, "running": 0, "pool_capacity": 16, "max_threads": 16 }/, body.split("\r\n").last)
+    assert_match(/{"started_at":"\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z","backlog":0,"running":0,"pool_capacity":16,"max_threads":16}/, body.split("\r\n").last)
   ensure
     if UNIX_SKT_EXIST
       cli.launcher.stop